import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

/**
 * @description:
 * @Author yyp
 * @time
 */
public class test {
    public static void main(String[] args) {
        List<Integer> a = new ArrayList<>();
        a.add(1);
        //迭代器
        Iterator iterator = a.iterator();
        iterator.hasNext();
    }
}


